Manometric Subtypes of Ineffective Esophageal Motility

Ineffective esophageal motility (IEM) is characterized by well-defined manometric criteria. However, much variation exists within the diagnosis: Some patients exhibit exactly the required five weak swallows to make the diagnosis. Others show consistently ineffective swallows with total absence of any normal swallow. "We hypothesize" there are two different manometric subtypes of IEM; IEM Alternans (IEM-A) and IEM Persistens (IEM-P).

A total of 231 IEM patients were identified by high-resolution manometry (HRM). IEM defined by distal contractile integral (DCI) <450 mm Hg/s/cm in ≥50% of test swallows. Abnormal reflux study was defined by excess total number of reflux episodes, abnormal esophageal acid exposure, or positive symptom association.

A total of 195 (84%) patients had IEM-A and 36 (16%) had IEM-P. A striking gender difference with 34% of IEM-A being males compared to 53% of IEM-P. (P=0.03). Mean age of IEM-P (59.6 years+/-13.1) was greater than IEM-A (55.5 years+/-13.6) (P=0.04). Mean lower esophageal sphincter (LES) resting pressure was significantly lower in IEM-P (20.8 mm Hg+/-1.4) than IEM-A (29 mm Hg+/-1.2) (P=0.002). There was no difference in LES-integrated relaxation pressure (IRP), bolus transit, or manometric presence of hiatal hernia between the two groups. Out of 146, 89 (61%) patients had abnormal reflux study. Esophageal acid exposure in upright position was significantly higher in IEM-P than IEM-A (3.5 vs. 1.7%, P=0.04). Poor gastric acid control on proton pump inhibitor (PPI) was more prevalent among IEM-P patients (58%) than IEM-A (27%) (P=0.007). In subgroup analysis of 41 IEM patients with dysphagia, DCI for liquid swallows was significantly lower in IEM-P (111+/-142 mm Hg/s/cm) compared to IEM-A (421+/-502 mm Hg/s/cm) (P=0.04), lower mean LES resting pressure in IEM-P (16.6+/-9 mm Hg) than IEM-A (31.7+/-18 mm Hg) (P=0.01).

There are two distinct manometric IEM subtypes; IEM-P with an older male predominance, more advanced reflux disease, weaker LES, and worse response to PPI; likely a more advanced manifestation than IEM-A. However, the question if there are different etiologies underlying the two subtypes remains to be answered.